QR Code, abbreviated form Quick Response Code, is one of the most widely used barcode type of 2D barcodes. This barcode type was invented by Denso Wave and it was released with the initial aim of being a symbol in 1994. Nowadays, QR Code can contain a considerably greater volume of information than other linear barcodes.

Besides, QR Code image can be split into several small images, and the original data can be decoded by those small images accurately at high speed. Furthermore, it is easily interpreted by scanner equipment, such as QR scanners, mobile phones with a camera, and smart phones.

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Structure of QR Code

Each QR Code is constructed of function patterns and encoding region. The function patterns consists of quiet zone, finder pattern, separator, timing patterns and alignment patterns, while the encoding region is comprised of format information, data and error correction codewords and version information.

Usage of QR Code

Since QR Code, compared with standard UPC barcodes, has advantage of fast readability and large storage capacity, it is widely applied to all kinds of industries.

In recent years, it is commonly used in advertising, packaging, commercial tracking, entertaining, transport ticketing, product marketing and in-store product labeling. Besides, it can also be applied to store personal information by government. Moreover, it may appear in magazines, on signs, buses, business cards, or almost any object about which users might need information.

Encodable Characters of QR Code

QR Code has a high capacity of encoding data, which contains four encodable character sets:

The Extended Channel Interpretations (ECIs) enables QR Code to encode multiple character sets apart from the default encodable set, and other data interpretations.

Error Correction Level of QR Code

To detect QR Code errors, the Reed-Solomon is recommended to be applied. When the barcode image is partially dirty or damaged, QR Code has the capacity to restore the data. There are four levels of Reed-Solomon error correction for users to select:

Level L: 7%

Level M: 15%

Level Q: 25%

Level H: 30%

Size of QR Code

QR Code barcode has forty sizes, each of which ranges from Version 1 to Version 40. And each Version is increasing in steps of 4 modules per side. The increasing formula is "Version N = (17 + 4N)(17 + 4N)" (in modules) (N indicates 1, 2.....40).

Both QR Code and Data Matrix are two-dimensional barcode, which are able to contain a considerably great volume of information with a small area. However, there are many differences between Data Matrix and QR Code. More details are presented in the following table: